The invention relates to assemblies including multiple "AC snap receptacles" connected to ordinary AC power conductors and also to printed circuit boards carrying transient surge suppressor circuitry, filter circuitry, or other circuitry.
So-called "power strips" including a plurality of power receptacles and also including pulse suppressor circuits are widely used to protect sensitive electrical equipment such as computers, microwave ovens, television sets, and stereo circuitry from damage due to lightning-induced voltage surges and power surges on the AC power lines. Such power strips contain a power cord that plugs into an ordinary household AC power outlet, and the sensitive equipment is plugged into the various AC power outlets or receptacles of the power strip. The market for such power strips is highly competitive. Most power strips are manufactured outside of the United States in countries with low labor costs because manufacture of present power strips requires a large amount of human labor. Those skilled in the art of engineering improvements for power strip products and the like usually attempt to reduce the cost of manufacture by reducing the amount of human labor required, to avoid the substantial inconvenience associated with overseas manufacture of a product marketed in the U.S.
Power strips and like products frequently use plastic AC snap receptacles marketed under the trademark "AMP". An exploded view of such AC snap receptacle 10 is shown in FIG. 1A. Snap receptacle 10 includes a rectangular housing 10A and a separate snap-on retainer 10B. The bottom surface (not shown) of housing 10A contains three slots for receiving the two "hot" prongs and the ground prong of a typical three wire male plug connector of an appliance or other power utilization device. The three female connector elements for receiving the two "hot" prongs and the ground prong are attached to integral plastic support members inside body 10. Each female connector element is integral with two upwardly extending insulation displacement/connector prongs 12. Each insulation displacement/connector prong 12 has a "knife blade" edge defining an elongated slot, so that when an insulated conductor 11 is forced downward into the slot as shown in FIG. 1A, the knife edges cut through the insulation and contact the inner copper conductor of the wire 11. Each insulation displacement/connector prong 12 also forms a U-shaped contact channel along which the outer edge of a male tab friction fit connector can slide during insertion. Normally, the AC snap receptacle housing 10 is "snapped" into a rectangular opening in a mounting panel, and is retained in place by latching elements 13.
Snap-on retainer 10B includes four hooked legs 15, the hook ends of which resiliently yield to allow snap-on retainer 10B to be forced onto the assembly shown in the lower portion of FIG. 1A. The hooked ends of legs 15 snap into grooves 16 on either side of the housing 13 when snap-on retainer 10B is fully inserted and locked in place. Three connector-receiving slots 14 are provided in the upper surface of snap-on retainer 10B to receive three male tab friction fit connectors 21 that are connected to wires 20 or to a printed circuit board. The two modes of connecting electrical power to snap receptacle 10 shown in FIGS. 1A and 1B are mutually exclusive, because the lower ends of the male tab friction fit connectors 21 abut the upper insulated surfaces of wires 11, so the outer edges of male tab friction fit connectors 21 cannot slide between and frictionally fit into the two opposed U-shaped channels of the insulation displacement/connector prongs 12.
FIG. 2 shows an exploded side view diagram of the closest prior art, presently marketed by the assignee. The assembly 17 shown in FIG. 2 is a power strip having a mounting panel 24 into which a suitable number of AC snap receptacles 10 of the type shown in FIGS. 1A and 1B are mounted. An on/off switch 25 having three upwardly extending conductive prongs also is mounted in panel 24. A printed circuit board 30 containing a transient voltage suppressor circuit including a number of large capacitors 26, a number of metal oxide varistors 27, several large inductors 27, and a number of Transorb semiconductor junction pulse suppressor diodes 28 are interconnected to perform a suitable transient voltage suppression function. (For convenience, the housing covering printed circuit board 30 is omitted in FIG. 2.) The insulated conductors 11 coming from the receptacles 10 installed in the mounting panel 24 are connected to the copper conductors 11A by solder connections to suitable metalization strips on the upper and lower surfaces of printed circuit board 30. Each of the three power conductors 11 is connected in parallel with a plurality of snap receptacles 10 in the manner shown in FIG. 1A.
Due to the fact that one of the large capacitors 26 extends downward so as to block routing of power conductors 11, the two left AC snap receptacles 10-1 and 10-2 are not directly connected to power conductors 11. Instead, the connection shown in FIG. 1B is utilized for each of receptacles 10-1 and 10-2, with male tab friction fit connectors such as 21 inserted into connector-receiving slots 14 in the upper surfaces of their snap-on retainers 10B. The upwardly extending conductive prongs of on/off switch 25 also are inserted in corresponding female connectors 25A to effectuate mounting of printed circuit board 30 on mounting panel 24.
The stripped ends 11A of power conductors 11 extend through three holes 31 in printed circuit board 30, as shown in FIG. 2A, which is an enlarged view of detail 2A in FIG. 2. A considerable amount of manual assembly effort is required to effectuate bending of the stripped ends 11A of power conductors 11 upward and insertion of them through holes 31. Since most of the printed circuit board has already been efficiently soldered by means of a wave soldering machine, the areas to be soldered around holes 31 must be masked against solder flow by hand. The labor intensive operation of applying suitable amounts of solder masking material exposing only the areas to which the stripped ends 11A of the power conductors are to be soldered must be performed. The soldering is performed after printed circuit board 30 has been mounted as described above, and after the soldering operation the solder masking material must be removed.
It would be desirable to simplify the manufacture of products using power receptacles of the type described above.